look in the manual it should tell you the scheduled time frame or mileage to change it. another good way to determine if it needs to be changed out is, to wait until engine cool, then open the radiator cap and see if the fluid is clear, if it is cloudy or dirty looking then change it. the temp gauge is only going to tell you the current temp range of the engine not when the coolant needs to be flush or changed.

The first person who answered your question is another Yahoo non-mechanic who apparently can't read an automotive owners manual..

It's best to drain, flush and CLEAN the cooling system with one part powered acid cooling system cleaner every 100,000 miles to get the corrosion, rust and scum out of the cooling system.

ALWAYS use antifreeze from the dealer of your car. The use of discount store antifreeze will not mix with factory long live type.

It can get old and the most important thing is that it stops corroding the aluminium parts etc, as this coat money eating away the heads and water pump etc. so it you do it you could leave it into say 5 years , as I do that.

I never change that . I just can not see any good reason to do it .

You're overdue. Ford recommends it at 100K. The coolant itself doesn't wear out. But the additives do. Once those are gone the entire system starts to corrode. Read these two articles on coolant and testing

http://ricksfreeautorepairadvice.com/tes...

http://ricksfreeautorepairadvice.com/ant...

I have an 01 Explorer sport, 130,000. How often should I change the coolant in my car, and how do I know if its starting to go bad? Gauge says its running at operating temperature(not sure how accurate Ford gauges are though).